scope:

The design of steel fiber-reinforced concrete (SFRC) slabson- ground (G-SFRC) and elevated SFRC (E-SFRC) slabs in the past three decades has resulted in a significant practical and engineering experience that has not been documented before. This report addresses various aspects of analysis, design, and construction of elevated slabs using steel fibers as the primary reinforcement. The benefits of these systems are discussed in terms of reduction in the number of joints; shrinkage control enhancement; ductility; improvements in the architectural design; and reduction of drop panels and beams, which results in easier forming and setup and, ultimately, in an economic and sustainable system.

The design procedures address the material and structural ductility aspects and their effect on the two-way slab mechanism. Test methods that are applicable to design include the three-point bending test as a measure of material ductility, and simply supported round slab as a measure of material and structural ductility. The discussion of these tests is followed by the procedures to predict the behavior during full-scale structural testing. The design guides for strainsoftening, deflection-hardening materials are also presented as the underlying basis for these systems.

The structural analysis approach to evaluate the nominal flexural strength of E-SFRC slabs is based on yield-line theory, and several cases of uniformly distributed loads, line, and point load are presented. Flexural strength calculations for failure patterns can be accomplished using the test data derived from both the three-point bending flexural test and/ or a test on a continuously supported round slab. Design examples are presented in Appendixes A through K in support of the structural analysis approach and the flexural strength calculations.

Four full-scale tests of elevated slabs are presented and discussed. Experimental results and model-based computed values are compared using numerical examples for the verification of the design. Full-scale testing procedures are presented that show the ability of deflection hardening SFRC to produce multiple cracks under flexure and, hence, use of inelastic post-cracking properties in the design process are discussed.